This is directed to detecting a plug placed in an electronic device without physically contacting the plug.
Many electronic devices provide functionality via accessories coupled to the electronic devices using a plug. For example, media players can include a jack into which an audio plug can be inserted to provide audio from the device to a speaker or headphone connected to the jack. As another example, laptop and desktop computers can include USB ports for receiving USB accessories such as input mechanisms (e.g., a keyboard and mouse), peripheral devices (e.g., a printer), storage media (e.g., external hard or solid state drives), or any other suitable accessory providing additional functionality to the device.
To provide the additional functionality, an electronic device may first detect the accessory device plug inserted into an appropriate aperture of the device and enable a state associated with the detected accessory device. One typical manner to detect a plug is to provide spring arms or other components in the device aperture that are placed in physical contact with the plug upon insertion of the plug. For example, an audio jack can include two or more conductive spring arms operative to create an electrically conductive connection with an inserted plug. A circuit can then detect that the two or more conductive spring arms have been shorted to determine that a plug was inserted in the device.
As the size of devices is reduced, however, space may not be available to provide spring arms or components for physically contacting a plug. Alternatively, the spring arms or components can limit the overall size of the electronic device. In addition, the physical contact of between the spring arms or other components and the plug can be a source of failure (e.g., fatigue failure after a particular number of plug insertion-removal cycles).